Window air conditioners that are readily removable are not considered permanently installed appliances, and we don’t inspect them unless they are confirmed as part of the sale of the property. Wall air conditioners are permanently installed and we check them. Here’s our top 7 most common defects found during a home inspection:

1) Single-outlet circuit rated, but on regular outlet - Units that are 120-volt  and 10,000 BTU or more are specified by the manufacturer to be on their own separate circuit because of the high amperage draw. It is noted on a plate on the side of the air conditioner, but it is often plugged into a regular duplex wall receptacle. 

2) Poorly sealed around opening - Light visible around the edges of the unit, loose seal material, or cracks in the accordion panel of a window air conditioner.

3) Not cooling or low temperature differential - The difference between the ambient room air and the cold air coming out of the air conditioner is called the “temperature differential,” and it should be 14º F or more if the unit is functioning properly. 

4) Connected to wall outlet with extension cord - Most units are specified by the manufacturer to only be directly connected to a wall receptacle. While there are heavier extension cords rated for wall/window air conditioner use, they are 6-feet or less.

5) Exterior side of unit exhausts into enclosed space - When the heat generated is dissipated into an enclosed or partially-enclosed area, such as a garage or carport, the efficiency of the system is reduced.

6) Condensate drainage problems - The water dripping from under the unit sometimes puddles on a walkway below or drips down an outside wall. Even worse, it can drip inside the wall unnoticed, causing wood rot and mold. And attempts to fix the problem are sometimes hilarious, like this one we saw during a recent weekend in Key West.

7) Connected to ungrounded (2-slot) receptacle - The 2-slot ungrounded receptacles found still found in many pre-1960 homes are safe and acceptable as long as only 2-prong cords are connected to them; but all wall/window air conditioners require grounding and have a 3-prong cord. The small grey conversion plug used to connect a 3-prong cord to a 2-slot receptacle, shown below, does not actually provide a ground. 

    Incidentally, we note in our report if a wall/window air conditioner does not have a heating mode, if it is in a room that does not have any installed heating appliance or duct from a central system in it. While it is not a defect, we want the homebuyer to know if it is not meant to be an all-seasons room. Also, rooms without permanently installed heat are not counted in the calculation of total square footage of conditioned space for a real estate transaction.

    Also, see our blog posts Why is my air conditioner not cooling enough? and What is the average life expectancy of a window unit air conditioner or heat pump? and How did homes stay cool in Florida before air conditioning?

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  To learn more about heating and air conditioning systems, see these other blog posts:

• How can I find out the SEER of my air conditioner? 

• My air conditioner won't turn on. What's wrong? 

• How can I find out the size of my air conditioner? 

• How can I find out the age of my air conditioner or furnace?

• How can I tell whether the condenser (outdoor unit) is an air conditioner or heat pump? 

• Where is the air filter for my central air conditioner and furnace? I can’t find it? 

• Does an old air conditioner use more electricity as it ages?  

• How can I find out the size of my air conditioner? 

• How can I find out the age of my air conditioner or furnace? 

• What is wrong with an air conditioner when the air flow out of the vents is low?

• Why has the thermostat screen gone blank? 

• Why does it take so long to cool a house when an air conditioner has been off for a while? 

• Will closing doors reduce my heating and cooling costs? 

    Visit our HEATING AND AIR CONDITIONING and COMMON PROBLEMS pages for other related blog posts on this subject, or go to the INDEX for a complete listing of all our articles.